DURHAM, N.C. (AP) - Duke's defense has to be better this season - if only because the Blue Devils couldn't get much worse than in 2012.

``Every Saturday this year is going to be a showcase for us, a showcase to prove what we've worked on in the offseason,'' cornerback Ross Cockrell said Tuesday.

They certainly had plenty to fine-tune, and the first chance to show what they've learned comes this weekend against crosstown Championship Subdivision opponent North Carolina Central.

Improvement on defense has been a top priority for Duke, which ranked 10th or worse in the Atlantic Coast Conference in all four of the major defensive stat categories.

No ACC team allowed more points per game last year than the Blue Devils, who gave up an average of 36. They surrendered at least 41 points in six of their final seven games last season, a blight on an otherwise breakout year in which they reached their first bowl since 1994.

``We haven't won very many 49-48 games,'' defensive coordinator Jim Knowles said. ``When the defense steps up, we win. We don't talk about the numbers a lot ... but we all know.''

Knowles hopes a change in the focus of its 4-2-5 defense will lead to better results.

In the two previous years, the defense has been driven by its safeties but the heart of this year's group will be a front six that features three redshirt seniors - including sixth-year end Kenny Anunike - and three redshirt juniors.

Their goal is to generate pressure and take some heat off a secondary in which Cockrell, a preseason all-ACC pick, is one of only two senior starters. Four freshmen - one redshirt and three first-year players - appear on the depth chart as possible backups at cornerback, but Cockrell says he isn't concerned about that inexperience.

``We have a good mix of old and young players,'' Cockrell said. ``We have guys who are veterans who know the schemes, understand the schemes and guys that are on the younger side that may not be as experienced and understanding reading concepts but are athletic, and fast and talented enough to go up and get the ball.''

Two of the key players Duke is counting on didn't play a snap last season: middle linebacker Kelby Brown missed the year after having knee surgery, and redshirt sophomore safety Jeremy Cash, who transferred from Ohio State, sat out in 2012 after his appeal to play immediately was denied by the NCAA.

Knowles says Cash can be the prototypical ``strike'' safety in Duke's three-safety alignment while Brown will be counted upon to lead the front six both with his play and his words.

``We talked about getting more from our front six - in today's game, those guys have to make tackles,'' Knowles said. ``Kelby's a guy who's a tackler.''

He'll be counted upon to strengthen a unit that showed some cracks late last season. Duke was 6-2 last October and in position to snatch the Coastal Division title before things went south.

In their season-ending five-game losing streak, the defense allowed 15 touchdowns that covered at least 20 yards - including an 82-yard pass in the final minute of the Belk Bowl loss to Cincinnati.

But quarterback Anthony Boone, who goes up against the first-string defense during practice, insists things have changed. The Duke defense, he says, has shown significant visible improvement on the practice field since then.